Vehicle and vehicle cooling system

Abstract

A vehicle includes a first cooling loop, a second cooling loop, and a controller. The first cooling loop includes a compressor and a chiller. The second cooling loop includes a valve and an evaporator. The second cooling loop extends from an input side to an output side of the chiller on the first loop. The controller is programmed to, responsive to operation of the chiller but not the evaporator, close and intermittently pulse open the valve each time a discharge pressure of the compressor exceeds a first threshold.

What is claimed is: 
     
       1. A vehicle comprising:
 a first cooling loop including a compressor and a chiller; 
 a second cooling loop including a valve and an evaporator, and extending from an input side to an output side of the chiller on the first loop; and 
 a controller programmed to, responsive to operation of the chiller but not the evaporator, close and intermittently pulse open the valve each time a discharge pressure of the compressor exceeds a first threshold. 
 
     
     
       2. The vehicle of  claim 1 , wherein the valve is disposed within the second loop between the evaporator and input side of the first loop. 
     
     
       3. The vehicle of  claim 1 , wherein the controller is further programmed to, responsive to each pulsing open of the valve, close the valve when the discharge pressure of the compressor drops to below a second threshold that is less than the first threshold. 
     
     
       4. The vehicle of  claim 1 , wherein the compressor is configured to power-off responsive to the discharge pressure of the compressor exceeding a shutdown threshold that is greater than the first threshold. 
     
     
       5. The vehicle of  claim 1  further comprising a traction battery, and wherein the chiller is configured to cool the traction battery. 
     
     
       6. The vehicle of  claim 1  further comprising a cabin, and wherein the evaporator is configured to cool the cabin. 
     
     
       7. A vehicle cooling system comprising:
 a first refrigerant loop including a first heat exchanger; 
 a second refrigerant loop including a valve and a second heat exchanger, and extending from high to low pressure sides of the first loop on opposing sides of the first heat exchanger; and 
 a controller programmed to, responsive to operation of the first but not the second heat exchanger, close and intermittently pulse open the valve at regular time intervals. 
 
     
     
       8. The system of  claim 7 , wherein the valve remains open for a predetermined time period each time the valve is pulsed open. 
     
     
       9. The system of  claim 7 , wherein the valve is disposed within the second refrigerant loop between the second heat exchanger and the high pressure side of the first loop. 
     
     
       10. The system of  claim 7 , wherein the first refrigerant loop includes a compressor and the controller is further programmed to, responsive to operation of the first hut not the second heat exchanger, intermittently pulse open the valve each time a discharge pressure of the compressor exceeds a first threshold. 
     
     
       11. The system of  claim 10 , wherein the controller is further programmed to, responsive to each pulsing open of the valve, close the valve when the discharge pressure of the compressor drops to below a second threshold that is less than the first threshold. 
     
     
       12. The system of  claim 7 , wherein the first heat exchanger is configured to cool a vehicle traction battery. 
     
     
       13. The system of  claim 7 , wherein the second heat exchanger is configured to cool a vehicle cabin. 
     
     
       14. A vehicle comprising:
 a first refrigerant loop including a chiller; 
 a second refrigerant loop including an evaporator and extending from an input side to an output side of the chiller on the first loop; 
 a valve disposed within the second loop between the evaporator and input side; and 
 a controller programmed to, responsive to operation of the chiller but not the evaporator, close and intermittently pulse open the valve. 
 
     
     
       15. The vehicle of  claim 14 , wherein the valve is intermittently pulsed open at regular time intervals. 
     
     
       16. The vehicle of  claim 14 , wherein the valve remains open for a predetermined time period each time the valve is pulsed open. 
     
     
       17. The vehicle of  claim 14 , wherein the first refrigerant loop includes a compressor and the controller is further programmed to, responsive to operation of the chiller but not the evaporator, intermittently pulse open each time a discharge pressure of the compressor exceeds a first threshold. 
     
     
       18. The vehicle of  claim 17 , wherein the controller is further programmed to, responsive to each pulsing open of the valve, close the valve when the discharge pressure of the compressor drops to below a second threshold that is less than the first threshold. 
     
     
       19. The vehicle of  claim 17 , wherein the compressor is configured to power-off responsive to the discharge pressure of the compressor exceeding a shutdown threshold that is greater than the first threshold.